11 replies to this topic

[Major Burkenshaw]

Right I have reached the stage in my project where I have hit a wall and i'm stuck. I have transplanted an spi engine into my '79 estate and i'm so nearly there to finishing that this last problem is driving me mad

All the following refers to a 2 plug ecu

The engine starts and runs ok but will not turn off unless I disconect the battery cable. I have traced through the wiring and have narrowed it down to the Main realy inside the relay pack. Basically what is happening is that the ecu is not noticing the loss of voltage when the ignition is turned off. I have tested the feed from the switch into the ecu and the 12v disapears as it should when you turn the key off.

I did notice that the circuit appers to be timed. My first though was that It was related to the fuel pump/priming circuit as I know this is a timed circuit, but I have isolated this circuit and the fault remains.

I narrowed it down to the main relay and its wiring and after testing I get the following results:

The ecu controls the earth side of the main relay(item 46 in haynes diagram) via pin 4 which is a white/pink(white/purple in Haynes)

With the ignition OFF there is a 12v feed on the white/pink wire

With ignition ON the feed drops down to 1.32v on the white/pink

After turning the ignition OFF and a delay of 30 seconds the voltage returns to 12v on the white/pink wire

But with the engine running and the igntion turned OFF the feed does not dispear and the engine remains running.

Today while working on the car i decided to test all was well with the cooling system and the car was runnig for approxiametly 5 mins. The car then died but restarted again for about 30 seconds then died completly. I checked the fuel as I know this was low, but all ok. Upon further investigation I found that a track had burnt out in the relay box.



The car now will not start as there is no feed to the coil, injector etc. due to the burnt out track. I don't know why this circuit burnt out though, as all was running well before hand. I am at a loss now as to what to do, I have checked all my wiring and it appears to be correct. There are however 2 wires on the engine loom plug which I cannot find in the Haynes manual:

White/Brown
Brown/Yellow

Now i'm pressuming that as the above white/pink wasn't the white/red the Haynes said it should be that these are also a different colour in the book. I have tried to find them in the book diagrams but have turned up nothing. I have searched the forum and information points to the white/pink wire being related to the imobiliser. I found out that the car did have an imobliser on it, but i would have thought that if this was the fault, the car would not run at all?

I hope this all makes sense and any help grately appreciated
Gary

[Sprocket]

I have never found any one diagram to be of use on just one car, they are all wrong in essence. You have to use some ingenuity and search several diagrams to get the information you need.

I'll have a look over this and get back to you, it may take some time.

Burnt out relay packs are known, i have one that has been repaired due to a similar track burning situation, that too came off a two plug ecu system. Things like that only happen where there is a bad connection or excessive current is drawn, there are no fuses in these circuits other than the fuseble links, one thing i made sure I changed whe i fitted the VEMS.

Deffo sounds like a wiring issue rather than the ECU. The voltages you report on the white pink wires suports this. The relay pack is supplied with a live with the ignition switch on IGN position, thats the white wire, the ecu then grounds the relay, so, what you end up with is, with the engine off and ignition on, 12v right up to the ECU where it goes no further. When the ECU grounds the wire, the 12v disappears, for want of a better word. What is actualy happening is that due to the resistance of the relay coil, the voltage has dropped, the ground pulling it down to zero, remove the ground and the whole wireand relay coil up to the ECU will reach full potential. From what you describe the ECU is functioning as it should.

[Major Burkenshaw]

Hmm I understand that the ecu grounds the white/pink wire to allow the relay to close. Would I be correct in assuming from my voltage readings that when the igntion is switched OFF, the ecu switches from providing an earth to supplying a 12v supply thus unlatching the relay? The timer function would fit into this idea by supplying 12v for a period of time to ensure the engine has stopped running.

After studying the diagram some more I notice that the ignition feed connects to the ecu via pin 11 Black/White and the purge valve via pin 21 also black and white. Currently the purge valve is not used on my project as I was under the understanding that it was for emissions control only. I might plug it in just to see if affects it in anyway, but I can't see it stoping the engine from turning off.

Sorry for my museings and as I said, I appreciate the help and understand your busy. I think I might post my entire wiring diagram for the project and see if it can be of some use.

Gary

Edit: I have remembered that the white/brown is oil pressure and the brown/yellow is charge w/light. I kept the original wires from the existing loom as they dont enter into the injection side of things. Doh!

Edited by Major Burkenshaw, 11 August 2007 - 10:01 PM.

[Sprocket]

Im on this right now, post back shortly

[Sprocket]

when you switch the ignition on, 12v supplied to the ECU on the white wire, pin number 11, this an ignition sense, it simply is there to determine igntion on or off. Main power to the ECU is brown pink wire on pin 28.

The ECU will sense the ignition when its switched on, the ecu waits for activity on crank sensor (starter turning over engine) then grounds pin4 the white pink wire, thus energising the main relay. This main relay puts 12v on to the injector, the coil, the purge relay, the stepper motor, pin28 on the ECU and if my memory serves right also the oxygen sensor relay. At this time the ECU grounds pin 20 black purple, the fuel pump relay. Also dependant on engine temperature the ECU grounds pin6 black pink wire, the manifold heater relay. Oxygen sensor relay grounded on pin36, black green. Injector fires, coil fires, fuel spark the engine starts

Switching off the ignition, the ECU senses no volts on pin 11 white, cuts fuel and spark, engine stops, ECU holds pin 4 white pink to ground, thus keeping the main relay energised, 12v still on pin 28 brown pink supplying the power to the ECU and stepper. Pre determined time delay on releasing the ground on pin 4 white pink to enable stepper to motor fully closed then open to the calculated 'crank' position. ECU releases the ground on Pin 4 white pink main relay opens dropping the 12v from ECU pin 28 brown pink, there is now no power onto the ECU, despite there being 12v on white pink. The ECU requires no power to retain its memory, hence why disconecting it from the loom will not re set the adaptive parameters, perhaps a prolonged power down, may be in the region of months, it may then loose its memory, nothing serious if it does.

If your wiring is correct, this is how it should work. Having a burnt relay pack could suggest it is not as does the engine running on, the ECU is simply not sensing the ignition switch is off.

Im finding it a little difficult to understand exactly whats what from your description, so, things to test.

I now have screen grab software so can post up the diagrams i swap between, as one is not the other and its not whats in the car, LOL, typical rover. Haynes manual seem to have their own which again is some what different, just to complicate things

One thing Rover did do, was they kept fairly good convention with the wire colours. You can most of the time once you know what colour is for what, take that onto another Rover car and it will be the same. So reading the diagrams, its a matter of following wire colours rather than the location of the pins/ relays. I have yet to see an SPi loom where the oxygen sensor relay is in the relay pack and the manifold heater relay is on the bulkhead, the ones i have seen are the other way round, that includes 2 J reg 92 SPi's. So as you can apreciate, reading the wiring diagrams for the engine management is some what difficult.

Going back to what you are seeing with the 12v on the white pink wire. A relay coil (simply a long piece of wire wound round an iron core) with 12v on one end and, the other end, for example, dangling in free air, the potential across the whole length of the wire is 12v, no current is flowing, it has nowhere to flow to. This is what you are measuring on pin 4 white pink with the ECU in the off state. With the ECU gounding this wire, current flows, generating a magnetic field in the coil. The voltage drops across this coil so explaining why you see nearly zero volts, too big a resistance and lttle current flows and nothing happens, too little resistance, large amounts of current flow, with it, generating heat at the weakest point (the element of a light bulb). Remove the ground and the potential of the whole coil/ wire again rises to 12v. It is a little more involved than that but I hope that helps you understand why you see the 12v with the engine off and zero ( low volts) with the engine on. It has nothing to do with the ECU supplying 12v, they dont. All ECUs which ever one, grounds the circuit rather than supplying 12v.

[GraemeC]

Sounds to me like the ECU is copntrolling the white/pink exactly as it should.

I'd be looking into the main relay being permanently earthed some other way (so always energised), regardless of the white/pink wire state or the subsequently controlled items (injector, coil, purge relay, stepper motor, etc) always having 12V. ie they are always live and just waiting for the engine to be turned over, obviously pulling the battery lead off will kill them and hence the engine.

Test - leave the ignition switch off and short the starter terminals - does the engine fire?

[Major Burkenshaw]

Sounds to me like the ECU is copntrolling the white/pink exactly as it should.

If you look at my readings I stated that the ECU is earthing the white/pink wire with the engine OFF but ignition ON, which contradicts what Mini Sprocket says should be happening. Going via his information then the ECU only grounds this wire when it detects activity at the crank speed sensor.

I have spliced into the loom from the engine loom plug that is located on the bulkhead where it would normally go into the passenger compartment loom. So the engine loom is as exactly as it came out of the donor car. I have NOT modifed any wires between the ecu, relay pack or sensors etc.

As stated above I tested the ignition feed to the ECU and it is operating exactly as you say it should Mini Sprocket.

Surely if the white/pink wire is being earthed somewhere else then testing this wire at any time would not give 12v as it is battery feed via the fuseable links located by the starter. The coil etc. do NOT have volatge when the key is removed.

I can see this isn't going to be easy to sort out

Below is every connection I have made to the loom from the existing wiring:

Brown/Slate(thick wire) connected via a inline fuse to the inertia switch and then to the fuel pump and then earthed.

Green/Blue - Output from ecu connected to cars temperature gauge

White/Red - Taken form old strarter solenoid on wing and connected to white/red of engine loom

White - Taken from old starter solenoid on wing and connected to white of engine loom

White/Slate - Connected to acclerator pedal switch and then to earth

The charge warning light wire and the oil pressure circuit do not input into the ecu function so I have kept as per the original 1979 wiring.

Edit: I have solved the probelm that caused the relay pack to burn out, but still strugling with it not turning off. The Haynes manual diargram and what i have on the ecu is completely different

Edited by Major Burkenshaw, 17 August 2007 - 02:11 PM.

[Sprocket]

White - Taken from old starter solenoid on wing and connected to white of engine loom

THIS IS YOUR PROBLEM!!!!!!

This white on the engine loom needs to be fed from the ING position on the starter switch. If you look at any of the Mini wiring diagrams you will see that the 'white' is always an ignition feed and brown is a battery feed.

What's hapening is that the ignition sense input on the ecu is not dropping resulting in the engine not switching off.




Going back to the white pink before the engine is started, what you experience with it grounding before the engine is turning over, this may well be the case on the two plug ECUs, infact, i cant actualy recall checking it, though, how i described it previously is how i have the VEMS controlling it.

[Major Burkenshaw]

White - Taken from old starter solenoid on wing and connected to white of engine loom

THIS IS YOUR PROBLEM!!!!!!

This white on the engine loom needs to be fed from the ING position on the starter switch. If you look at any of the Mini wiring diagrams you will see that the 'white' is always an ignition feed and brown is a battery feed.

What's hapening is that the ignition sense input on the ecu is not dropping resulting in the engine not switching off.




Going back to the white pink before the engine is started, what you experience with it grounding before the engine is turning over, this may well be the case on the two plug ECUs, infact, i cant actualy recall checking it, though, how i described it previously is how i have the VEMS controlling it.

As now stated twice in the above posts, the igntion feed is controled by the switch and is doing exactly what it should be doing.

I'm going to sort throught the wiring and pin functions of the ecu using my Autodata cd as the Haynes electrical diagram is not relevant.

Thanks for your efforts to help I'll let you know what the problem was when i've sorted it out.

[Sprocket]

I am confused as to which white wire on a starter solenoid is on with the igntion and off without???

Without being there and working through it my self, you are on your own im afraid.

Hope you get it fixed soon

[Major Burkenshaw]

Again thanks for your input, I mainly wanted to clarify ECU function as the electrical systems I work with are alot different to the MEMS system. Lol, If only I could multiplex the mini

[yasan39]

Right I have reached the stage in my project where I have hit a wall and i'm stuck. I have transplanted an spi engine into my '79 estate and i'm so nearly there to finishing that this last problem is driving me mad

All the following refers to a 2 plug ecu

The engine starts and runs ok but will not turn off unless I disconect the battery cable. I have traced through the wiring and have narrowed it down to the Main realy inside the relay pack. Basically what is happening is that the ecu is not noticing the loss of voltage when the ignition is turned off. I have tested the feed from the switch into the ecu and the 12v disapears as it should when you turn the key off.

I did notice that the circuit appers to be timed. My first though was that It was related to the fuel pump/priming circuit as I know this is a timed circuit, but I have isolated this circuit and the fault remains.

I narrowed it down to the main relay and its wiring and after testing I get the following results:

The ecu controls the earth side of the main relay(item 46 in haynes diagram) via pin 4 which is a white/pink(white/purple in Haynes)

With the ignition OFF there is a 12v feed on the white/pink wire

With ignition ON the feed drops down to 1.32v on the white/pink

After turning the ignition OFF and a delay of 30 seconds the voltage returns to 12v on the white/pink wire

But with the engine running and the igntion turned OFF the feed does not dispear and the engine remains running.

Today while working on the car i decided to test all was well with the cooling system and the car was runnig for approxiametly 5 mins. The car then died but restarted again for about 30 seconds then died completly. I checked the fuel as I know this was low, but all ok. Upon further investigation I found that a track had burnt out in the relay box.



The car now will not start as there is no feed to the coil, injector etc. due to the burnt out track. I don't know why this circuit burnt out though, as all was running well before hand. I am at a loss now as to what to do, I have checked all my wiring and it appears to be correct. There are however 2 wires on the engine loom plug which I cannot find in the Haynes manual:

White/Brown
Brown/Yellow

Now i'm pressuming that as the above white/pink wasn't the white/red the Haynes said it should be that these are also a different colour in the book. I have tried to find them in the book diagrams but have turned up nothing. I have searched the forum and information points to the white/pink wire being related to the imobiliser. I found out that the car did have an imobliser on it, but i would have thought that if this was the fault, the car would not run at all?

I hope this all makes sense and any help grately appreciated
Gary

problem is on the your ECU put a new one